#pragma once

#include <iostream>
#include <vector>
#include <pthread.h>
#include <semaphore.h>

static const int N = 50;

template <class T>
class RingQueue
{
private:
    std::vector<T> _ring;
    int _cap;
    sem_t _data_sem;
    sem_t _space_sem;
    int _c_step;
    int _p_step;

    pthread_mutex_t _c_mutex;
    pthread_mutex_t _p_mutex;

    void P(sem_t &s)
    {
        sem_wait(&s);
    }
    void V(sem_t &s)
    {
        sem_post(&s);
    }
    void Lock(pthread_mutex_t &m)
    {
        pthread_mutex_lock(&m);
    }
    void Unlock(pthread_mutex_t &m)
    {
        pthread_mutex_unlock(&m);
    }

public:
    RingQueue(int num = N) : _ring(num), _cap(num)
    {
        sem_init(&_data_sem,0,0);
        sem_init(&_space_sem,0,num);
        _c_step = _p_step = 0;

        pthread_mutex_init(&_c_mutex,nullptr);
        pthread_mutex_init(&_p_mutex,nullptr);

    }
    void push(const T &in)
    {
        P(_space_sem);
        Lock(_p_mutex);
        _ring[_p_step++] = in;
        _p_step%=_cap;
        Unlock(_p_mutex);
        V(_data_sem);
    }
    void pop(T* out)
    {
        P(_data_sem);
        Lock(_c_mutex);
        *out = _ring[_c_step++];
        _c_step%=_cap;
        Unlock(_c_mutex);
        V(_space_sem);
    }
    ~RingQueue()
    {
        sem_destroy(&_data_sem);
        sem_destroy(&_space_sem);

        pthread_mutex_destroy(&_c_mutex);
        pthread_mutex_destroy(&_p_mutex);
    }
};